Hi,
I'm looking for the following:
An 18650 battery shield that can hold four 18650 batteries in parallel. The shield needs to have an inbuilt BMS to ensure the batteries are balanced.
An MPPT charger. I have a 12V 20-watt solar panel that will be connected to the charger.
Ideally, the MPPT charger will need to have outputs of 3.3V, 5V and 12V. The 3.3V will be used to power up an ESP32, the 5V will be used for numerous sensors, and the 12V will be used to power an anemometer that operates between 12V to 20V.
I need a fair bit of redundancy in the capacity as the weather station will need to be able to run in darkness and for multiple days in a row of completely overcast conditions.
What are your suggestions?
Thanks for your help!
You don't need to worry about balancing if the cells are in parallel. Just use a single cell charger (Adafruit and Sparkfun sell solar LiPo chargers, among others).
Balancing is required for series connections.
Thanks for the tips! I will have a look at the suggested websites.
I visited before mentioned sites but, unfortunately, nothing is suitable for my project.
I'll just recap and hopefully it will become clear.
I want to build an automatic weather station (AWS) based on an ESP32
I have a 12V/10 W solar panel that will be connected to a MPPT solar charger. (Yes the input needs to be suitable for 12V)
The MPPT charger will need to have protection against over and under-voltage (To protect the 18650 batteries)
It would be great if the MPPT solar charger has a 3.3V, 5V and 12V output
Obviously, the weather station will need to be able to run whilst the four 18650 batteries are charging.
There will also need to be protection so that the batteries won't drain overnight.
Can somebody make a suggestion for a good MPPT charger and battery holder that meets the aforementioned criteria?
It doesn't need to be the cheapest but I'm looking for something reliable that will function for many years to come.
Thank you very much for your help!
If you really need MPPT then it'll probably have to be done in two stages.
Use a 12v solar MPPT charger to charge a 12v lithium (motorcycle style integrated BMS) or small lead acid battery, then use buck converters to generate the 5v and 3.3v outputs.
If a multi-year life is important then choose LiFePO4 for the 12v battery.
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